Expression and Activity Analysis of the Catalytic Domain of PTP1B

The amino acid sequence (1-301aa) coding the human PTP1B catalytic domain (PTP1Bc) was obtained from the GenBank. The PTP1Bc gene was constructed by overlapping PCR, then inserted into vector pET-22b (+) and expressed efficiently in E. coli BL21 (DE3) under the optimization condition after IPTG induction. The proteins were expressed mainly as inclusion bodies with the yield of more than 30% of total bacterial proteins. The expressed products were purified through Ni2+-affinity chromatographic column. After purification, the purity of the proteins was more than 95%. The result of western blotting confirmed that the purified proteins could specially combine with anti-PTP1B antibody. The enzyme activities experiment showed that the protein had phosphatase activities. The gene construction, expression, and purification of PTP1Bc may provide basis for further study of its functions.